Borlaug Barry A, Melenovsky Vojtech, Russell Stuart D, Kessler Kristy, Pacak Karel, Becker Lewis C, Kass David A
Division of Cardiology, Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA.
Circulation. 2006 Nov 14;114(20):2138-47. doi: 10.1161/CIRCULATIONAHA.106.632745. Epub 2006 Nov 6.
Nearly half of patients with heart failure have a preserved ejection fraction (HFpEF). Symptoms of exercise intolerance and dyspnea are most often attributed to diastolic dysfunction; however, impaired systolic and/or arterial vasodilator reserve under stress could also play an important role.
Patients with HFpEF (n=17) and control subjects without heart failure (n=19) generally matched for age, gender, hypertension, diabetes mellitus, obesity, and the presence of left ventricular hypertrophy underwent maximal-effort upright cycle ergometry with radionuclide ventriculography to determine rest and exercise cardiovascular function. Resting cardiovascular function was similar between the 2 groups. Both had limited exercise capacity, but this was more profoundly reduced in HFpEF patients (exercise duration 180+/-71 versus 455+/-184 seconds; peak oxygen consumption 9.0+/-3.4 versus 14.4+/-3.4 mL x kg(-1) x min(-1); both P<0.001). At matched low-level workload, HFpEF subjects displayed approximately 40% less of an increase in heart rate and cardiac output and less systemic vasodilation (all P<0.05) despite a similar rise in end-diastolic volume, stroke volume, and contractility. Heart rate recovery after exercise was also significantly delayed in HFpEF patients. Exercise capacity correlated with the change in cardiac output, heart rate, and vascular resistance but not end-diastolic volume or stroke volume. Lung blood volume and plasma norepinephrine levels rose similarly with exercise in both groups.
HFpEF patients have reduced chronotropic, vasodilator, and cardiac output reserve during exercise compared with matched subjects with hypertensive cardiac hypertrophy. These limitations cannot be ascribed to diastolic abnormalities per se and may provide novel therapeutic targets for interventions to improve exercise capacity in this disorder.
近半数心力衰竭患者射血分数保留（HFpEF）。运动不耐受和呼吸困难症状最常归因于舒张功能障碍；然而，应激状态下收缩功能和/或动脉血管舒张储备受损也可能起重要作用。
HFpEF患者（n = 17）和无心力衰竭的对照受试者（n = 19）在年龄、性别、高血压、糖尿病、肥胖及左心室肥厚情况方面基本匹配，接受极量直立运动心肺功能测试及放射性核素心室造影以确定静息和运动时的心血管功能。两组静息心血管功能相似。两者运动能力均有限，但HFpEF患者下降更显著（运动持续时间180±71秒对455±184秒；峰值耗氧量9.0±3.4对14.4±3.4 mL·kg⁻¹·min⁻¹；均P<0.001）。在匹配的低水平工作量时，尽管舒张末期容积、每搏输出量和收缩性有相似升高，但HFpEF受试者心率和心输出量增加约少40%，全身血管舒张也较少（均P<0.05）。HFpEF患者运动后心率恢复也显著延迟。运动能力与心输出量、心率和血管阻力的变化相关，但与舒张末期容积或每搏输出量无关。两组运动时肺血容量和血浆去甲肾上腺素水平升高相似。
与匹配的高血压性心肌肥厚受试者相比，HFpEF患者运动时变时性、血管舒张和心输出量储备降低。这些限制不能单纯归因于舒张异常，可能为改善该疾病运动能力的干预措施提供新的治疗靶点。
